Terminal for electrical installations

ABSTRACT

Prior art terminals with operating buttons and a contact member movable against the force of a spring are relatively bulky and complex. It is proposed to provide a part of a curved leaf spring as the contact member having at least one aperture fitted in such a way above the conductor guide that an edge of the aperture acts as the contact member. This design also permits the contacting of thin conductors.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a terminal for electrical installations,particularly for applied computer science, having a contact member whichcan be moved in a housing and which, under the force of a spring, can bepressed against a guide for a conductor which is open in the directionof the contact member, the contact member being part of a leaf springwhich is held in the housing and is provided with an opening which isarranged in such a manner with respect to the guide for the conductorthat an edge is used as the contact member and can be placed against theconductor.

Terminals with actuating keys are known. As a rule, these consist of aU-shaped component which surrounds a guide duct for the conductor and,by way of the leg facing away from the key part, forms the contactmember which, under the force of a spring, is pressed into the guideduct for the conductor for contacting it.

The manufacturing of such constructions requires relatively highexpenditures. Mainly, they will no longer allow any reliable contactingwhen the diameters of the conductors become very thin, which isparticularly the case in applied computer science and communicationstechnology. The space requirement of the known construction is alsorelatively high. Therefore, if a large number of connections isrequired, which is the case in communications technology, the spacerequirement for such terminals will become considerable.

A terminal of the initially mentioned type is also known (U.S. PatentDocument U.S. Pat. No. 5,069,638). There, a leaf spring is providedwhich is clamped on one side into a housing opening and which has anopening (or a recess) whose upper edge, as the contact member, rests ina clamping manner against the conductor which, on the other side, isheld on the wall of a guide in the housing. Since, in this type ofconstruction, only an opening for the guiding-through of the conductoris provided, it becomes necessary to clamp the end of the leaf springwhich is not provided with the opening fixedly in the housing.

The invention is based on the object of developing a terminal of theinitially mentioned type in such a manner that, while the spacerequirement is low, it can also be used for the secure contacting ofthin conductors.

For achieving this object, the leaf spring of a terminal of theinitially mentioned type is provided with rectangular apertures whichare arranged below one another in an aligned manner. The leaf spring isplaced in a curved shape on the guide for the conductors such that oneof the apertures is used as a clamping member for fastening the leafspring on the guide for the conductor, and an edge of the other apertureforms the contact member. The curved leaf spring is inserted between thebottom of a shaft in the housing and an actuating key. This embodimentis extremely simple. However, it permits the implementation ofrelatively high contact pressures since, as a result of the use of aleaf spring, high elastic forces are available and the contact memberonly has a small contact surface. This embodiment is thereforeadvantageous particularly for contacting thin conductors which are alsoheld securely in terminals according to the invention.

The construction is particularly advantageous if, as a furtherdevelopment of the invention, the conductor guide, in each case,consists of two parallel strip profiles which are provided with anapproximately V-shaped cross-section and which are connected with aconnection contact. The leaf spring can be clamped in a simple manner byits aperture on these strip profiles. A conductor placed in theconductor guide can, on the one hand, be perfectly contacted with theedge of the second aperture forming the contact member, but, on theother hand, can also be fixedly pressed into the V-shaped indentation ofthe strip profile and can be held there.

In the case of this embodiment, it is advantageous as a furtherdevelopment of the invention to provide the actuating key with plug-inopenings for the conductors to be connected which are aligned with thelongitudinal direction of the strip profiles. No additional space istherefore required transversely to the actuating direction of theactuating key.

In a further development of the invention, the leaf spring may beconstructed in one piece with a second leaf spring and may be providedwith a separating cut extending between the strip profiles. Despite thearrangement of only one leaf spring part, this construction also allowsthe contacting of conductors of different diameters, which naturallywould also be possible when two leaf springs are used for the two stripprofiles forming the conductor guide. However, the latter constructionwould require higher expenditures with respect to the manufacturing aswell as with respect to the mounting.

In a further development of the invention, the connection contact may beconstructed in one piece with the strip profiles and may be providedwith at least one detent for the locking on the housing. This permits arelatively simple manufacturing.

In this case, the connection contact may be constructed as a solder lugprojecting out of the housing. However, it may also be provided with twocontact studs for the direct plugging of printed circuit boards, inwhich case these contact studs may also be arranged at 900° or at 180°with respect to the longitudinal direction of the conductor guides, thatis, with respect to the longitudinal direction of the strip profiles.This measure permits the plugging-in of printed circuit boards also atan angle with respect to the plug-in direction for the conductors.Finally, as a further development of the invention, the housing may beprovided, on the side opposite the actuating key, with a plug-in openingfor the counterplugging of conductors which are aligned with theconductor guides.

According to various embodiments, the invention is illustrated in thedrawings and will be explained in the following.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective, schematic partial view of a terminal strip withtwo terminals according to the invention;

FIG. 2 is an opened-up perspective view of the inside of one of theterminals of FIG. 1;

FIG. 3 is a cross-sectional view of a terminal of FIG. 1 and 2 in asectional view according to Line III--III of FIG. 5;

FIG. 4 is a sectional view of the terminal of FIG. 3 along intersectionline IV--IV;

FIG. 5 is a top view of the terminal strip of FIG. 1, in which case thefirst of the terminals is illustrated without any actuating key;

FIG. 6 is a frontal view of the leaf spring used in the embodiment ofFIGS. 1 to 5;

FIG. 7 is a lateral view of the leaf spring of FIG. 6 in the conditionbefore the installation into the terminal;

FIG. 8 is a perspective representation of the conductor guides used inthe case of the terminal of FIGS. 1 to 5 with the connection contact inthe form of a solder lug mounted on the conductor guides;

FIG. 9 is a view of a modified embodiment of a terminal according to theinvention in which the connection contact is designed in the shape oftwo contact studs arranged while forming a fork-shaped receiving devicewhich contact studs are used for the direct plugging of printed circuitboards;

FIG. 10 is a representation of the conductor guides with the contactstuds of FIG. 9;

FIG. 11 is a view of a modified embodiment of the conductor guides witha solder lug arranged in-between;

FIG. 12 is a view of another variant of the conductor guides having afork-shaped plug-type stud which, however, is at an angle of 90° withrespect to the longitudinal direction of the conductor guides;

FIG. 13 is a view of a variant of the embodiment of FIG. 12 in which theplug-in studs are displaced by 180° with respect to the longitudinaldirection of the conductor guides, that is, in parallel to them; and

FIG. 14 finally is a view of another variant of a terminal according tothe invention in which the countercontact does not take place by meansof solder lugs or contact studs but by a direct counterplugging ofadditional conductors.

DETAILED DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 8 show a terminal 1 which is part of a terminal strip 2 whichis provided with several terminals which are all arranged in parallel toone another in the terminal strip 2. The embodiment shows only theterminal strip 1 and another terminal strip 3. Since all terminals havean identical construction, the following description is limited toterminal 1.

FIGS. 1 to 5 illustrate that each terminal and also terminal 1 arearranged in a shaft-type cavity (hereinafter shaft) 4 within the housingof the terminal strip 2, and that an actuating key 5 is held in theshaft 4 to be displaceable in the direction of the arrows 6. Theactuating key 5 has two openings 7 which have a circular design in theembodiment and widen slightly conically in the upward direction. Theseopenings 7 are aligned with two strip profiles 8 made of a conductivematerial which are both (see also FIG. 8) connected in one piece with aconnection contact 9 designed as a solder lug. In the area of theconnection web 10 to the two strip profiles 8, this connection contact 9has a detent 11 and, when the part illustrated in FIG. 8 is plugged inthe direction of the arrow 12 into the shaft 4, the connection contact 9can be locked by this detent in an opening of the shaft 4 and of thehousing 2 which is not illustrated in detail. In the same manner, theactuating key 5 also has laterally projecting detents 13 which have thepurpose of preventing the actuating key 5 from falling out in the upwarddirection after the insertion into the shaft 4.

Between the actuating key 5 and the bottom 4a of the shaft 4, a leafspring 14 (see FIG. 6 and 7) is inserted which, when inserted into theshaft 4, is prestressed and is therefore supported by means of its lowerend on the bottom 4a and by means of its upper end on a projection 30 ofthe actuating key 5. The leaf spring 14 in this case consists of twopartial leaf springs 14a and 14b which are separated from one another intheir function by a separating cut 15 and are each provided with twoapertures 16 and 17 and are connected with one another in one piece intheir lower area. The apertures 16 and 17 have a rectangularconstruction. Apertures 16 are constructed to be significantly largerthan apertures 17. The lateral edges of the apertures 16 and 17 arealigned with one another in such a manner that the apertures 16 and 17are in each case also disposed below one another in an aligned manner.

The dimensions of the apertures 17 are selected such that the upper andlower edges, in each case, engage the strip profiles 8 when the leafspring 14, as illustrated in FIGS. 2 and 4, is placed by way of bothapertures 16 and 17 onto the strip profiles 8. The leaf spring 14assumes a curved shape such that the upper edge 16a of each of theapertures 16 and forms a contact member with the strip profiles 8 andthe two edges of the aperture 17 extending in parallel to the edge 16arest against the strip profiles 8.

The strip profiles 8 are designed as conductor guides and areconstructed approximately in the form of grooves with an approximatelyV-shaped cross-section in which the ends of conductors, which are notshown, for the purpose of the contacting, can be introduced through theopenings 7 of the actuating key 5. The conductor ends will then be incontact inside the groove guide of the strip profiles 8 and are pressed,by the edge 16a (see FIG. 5), fixedly and securely against these stripprofiles 8 such that the edges 16a do not rest directly against thestrip profiles 8, as illustrated in FIG. 5, but rest against the outersurface of correspondingly slid-in conductors. FIG. 5 also shows clearlythat, because of the arrangement of the separating cut 15, conductors ofdifferent diameters can also be introduced through the openings 7, whichconductors can then also be contacted by the respective edge 16a of thepertaining leaf spring 14a or 14b.

The manufacturing of the terminal according to the invention takes placeautomatically in a simple manner such that first the leaf springs in acurved condition are placed on the assigned strip profiles 8, then thestrip profiles with the placed leaf spring with their connection contact9 are slid through the corresponding aperture 17 (FIG. 4) of the shaft 4until the detent 11 snaps in and then the actuating key 5 is fitted onwhich is secured in position by its detents 13, which reach behindcorresponding projections of the shaft 4. In this condition, the leafspring is situated in the shaft 4 under tension. When the key 5 isactuated, the upper position of the leaf spring is bent downward (thelower portion can be fixedly locked on the strip profiles 8 by theaperture 17), so that its edge 16a, which therefore also forms thecontact member, is removed from the strip profiles 8 and permits theintroduction of a conductor end.

FIG. 9 illustrates a modification of the terminal according to theinvention to the extent that no solder lug 9 is connected in one piecewith the two strip profiles 8, but two contact studs 18 which form afork-type plug-in device and are used as connection contacts. However,in this variant, the contact studs 18 do not project freely out of thehousing of the terminal strip 2 but are held in a housing 2' of aterminal strip which otherwise is also designed for several terminalsand which also surrounds the ends of the contact studs 18 which areguided in corresponding slots 19 of the housing 2'. In addition, thehousing 2' has an insertion slot 20 so that slid-in printed circuitboards may directly contact the contact studs 18. The remainingconstruction of the actuating key 5 and of the strip profiles 8 arrangedin a shaft 4 and serving as the conductor guide is identical to theembodiment of FIGS. 1 to 8.

FIGS. 11 to 13 show embodiments of a connection contact similar to FIG.8 or similar to FIG. 10. In this case, FIG. 11 illustrates that thesolder lug, which may also be a plug-in pin, is plugged in directlybetween the two strip profiles 8 and is connected with these either inone piece or by welding. In this case, the plug-in pin 21 has the detent11 for direct fastening on the housing. The design of the shaft must beadapted correspondingly.

FIG. 12 illustrates a variant of the contact studs of FIG. 10 in whichthe plug-in studs 22 project at 90° with respect to the longitudinaldirection of the strip profiles 8. In this variant, a direct contactwith printed circuit boards can be achieved by introducing the printedcircuit boards perpendicularly to the feeding direction of the conductorends to be connected.

FIG. 13 shows a variant in which the contact studs 23 are offset by 180°with respect to the plug-in direction of the conductors that is, theyare arranged in parallel to the strip profiles 8. A direct contact withprinted circuit boards can therefore take place from the same side fromwhich the connection of the conductors also takes place. Naturally, thehousing form must be correspondingly adapted to the contact studs ofFIGS. 12 and 13.

FIG. 14 shows the an embodiment in which the two conductors 24 and 25have different diameters and can be introduced through the openings 7 ofthe actuating key 5 in the manner described above. From the other side,conductors 26 contact the strip profiles 8 used as conductor guidesthrough openings 27 in the housing 2 of the terminal strip on the bottomof the shaft 4 which, in turn, extend in an aligned manner with respectto the longitudinal direction of the strip profiles 8. In this case, thesecuring of the position of the strip profiles 8 must be solved byseparate measures.

However, the strip profiles 8 may be secured in position by the leafspring 14 or its parts 14a, 14b with the apertures 17.

In the case of the embodiment illustrated in FIG. 14, an edge of theaperture 17 is also used to contact the conductor. It is illustratedthat the end of the conductor 26 is held between the lower edge of theaperture 17 and the strip profile 8. In the case of this variant, it isadvantageous to press away the edges of the aperture 17, which at firstare in a firm contact, by means of a suitable tool 28 before theconductor 26 is introduced. This embodiment is particularly recommendedwhen, for example, sensitive and high-expenditure data processingequipment is to be installed in areas to which free access exists beforethe actual final assembly. In this case, the data processing equipmentmay be applied to the terminal according to the invention by means ofcorresponding leads (such as 26) so that, at the time of the finalassembly, only the stationarily disposed conductors (such as 24, 25) canbe applied to the terminals in a simple manner and without any tools.

What is claimed is:
 1. An electrical connection terminal comprising:ahousing having an opening and a bottom portion; an electrical conductorguide arranged in the housing; and a conductive leaf spring arranged inthe housing and comprising a contact edge which is movable and which ispressed by a spring force Provided by said leaf spring against theconductor guide; the leaf spring defining rectangular apertures whichare aligned with each other, said leaf spring being arranged inengagement with said conductor guide such that the leaf spring is placedinto a curved form, a first of the apertures positioned adjacent to thebottom portion of the housing including edges for engagement with theconductor guide, and a second of the apertures positioned adjacent tosaid opening and including an edge forming said contact edge; whereinthe conductor guide comprises two longitudinal strips, the leaf springcomprises two sets of said first and second apertures, and the twolongitudinal strips engage respective sets of said first and secondapertures.
 2. The electrical connection terminal according to claim 1,wherein the conductor guide has a shape which is open in a direction ofthe contact edge.
 3. The electrical connection terminal according toclaim 1, wherein the leaf spring is inserted between the bottom portionof the housing and an actuating key located opposite said bottomportion.
 4. The electrical connection terminal according to claim 3,wherein the leaf spring has first and second opposing ends, and whereinsaid first end rests on said bottom portion of the housing and saidsecond end rests against the actuating key.
 5. The electrical connectionterminal according to claim 1, wherein the two strips are arrangedparallel to one another, have approximately V-shaped cross-sections, andare connected with a connection contact.
 6. The electrical connectionterminal according to claim 3, wherein the two longitudinal strips arearranged in parallel to one another, have approximately V-shapedcross-sections, and are connected with a connection contact, and whereinthe actuating key is provided with insertion openings for receivingconductors, said insertion openings being aligned with respect tolongitudinal directions of the longitudinal strips.
 7. The electricalconnection terminal according to claim 5, wherein the leaf spring isconstructed in one piece with a second leaf spring and wherein the leafspring and the second leaf spring are separated by a separating cutextending in a longitudinal direction and positioned between the twostrips.
 8. The electrical connection terminal according to claim 7,wherein the connection contact is constructed in one piece with thestrips and is provided with at least one detent for locking engagementwith the housing.
 9. The electrical connection terminal according toclaim 7, wherein the connection contact is designed as a solder lug. 10.The electrical connection terminal according to claim 7, wherein theconnection contact is provided with two contact studs for directengagement with printed circuit boards.
 11. The electrical connectionterminal according to claim 10, wherein the contact studs of theconnection contact are configured at an angle of 90° or 180° withrespect to the longitudinal direction of the strips.
 12. The electricalconnection terminal according to claim 3, wherein the housing isprovided, on a side opposite the actuating key, with a conductor plug-inopening arranged in alignment with the conductor guide.
 13. Theelectrical connection terminal according to claim 6, wherein the housingis provided, on a side opposite the actuating key, with conductorplug-in openings which are arranged in alignment with the stripprofiles.
 14. An electrical connection terminal, comprising:a housing; aconductor guide arranged in the housing; and a leaf spring arranged inthe housing, said leaf spring defining a pair of apertures aligned witheach other, said conductor guide extending through said pair ofapertures and placing said leaf spring into a curved shape; wherein oneof said apertures is disposed in a portion of said leaf spring which isbiased toward said conductor guide and an edge of said one of saidapertures is movable away from said conductor guide.
 15. The electricalconnection terminal according to claim 14, wherein another of said pairof apertures includes edges which clampingly engage said conductorguide.
 16. The electrical connection terminal according to claim 14,wherein the leaf spring is inserted between a bottom portion of thehousing and an actuating key located opposite said bottom portion. 17.An electrical connection terminal, comprising:a housing defining atleast one opening for receiving a conductor; a conductor guide arrangedin the housing essentially aligned with said at least one opening; and aleaf spring arranged in the housing, said leaf spring defining a pair ofapertures essentially aligned with each conductor guide, each conductorguide extending through said pair of apertures and placing said leafspring into a curved shape; wherein a first one of said pair ofapertures is located toward said opening in the housing and a second oneof said pair of apertures is located away from said opening in thehousing, and wherein said second one of said pair of apertures includesedges which clampingly engage said conductor guide.
 18. The electricalconnection terminal according to claim 17, wherein said first one ofsaid pair of apertures includes a portion which is biased toward saidconductor guide, and wherein said portion is movable away from saidconductor guide when said conductor is received in said opening.